Synchronizing Files Between Boot Environments

When you are ready to switch and
make the new boot environment active, you quickly activate the new boot environment
and reboot. Files are synchronized between boot environments the first time
that you boot a newly created boot environment. “Synchronize”
means that certain critical system files and directories might be copied from
the last-active boot environment to the boot environment being booted. Those
files and directories that have changed are copied.

Adding Files to the /etc/lu/synclist

Solaris Live Upgrade checks for critical files that have changed. If
these files' content is not the same in both boot environments, they are copied
from the active boot environment to the new boot environment. Synchronizing
is meant for critical files such as /etc/passwd or /etc/group files that might have changed since the new boot environment
was created.

The /etc/lu/synclist file contains a list of directories
and files that are synchronized. In some instances, you might want to copy
other files from the active boot environment to the new boot environment.
You can add directories and files to /etc/lu/synclist if
necessary.

Adding files not listed in the /etc/lu/synclist could
cause a system to become unbootable. The synchronization process only copies
files and creates directories. The process does not remove files and directories.

The following example of the /etc/lu/synclist file
shows the standard directories and files that are synchronized for this system.

The synclist file entries can be files or directories.
The second field is the method of updating that occurs on the activation of
the boot environment. You can choose from three methods to update files:

OVERWRITE – The contents of the active boot environment's
file overwrites the contents of the new boot environment file. OVERWRITE is
the default action if no action is specified in the second field. If the entry
is a directory, all subdirectories are copied. All files are overwritten.
The new boot environment file has the same date, mode, and ownership as the
same file on the previous boot environment.

APPEND – The contents of the active boot environment's
file are added to the end of the new boot environment's file. This addition
might lead to duplicate entries in the file. Directories cannot be listed
as APPEND. The new boot environment file has the same date, mode, and ownership
as the same file on the previous boot environment.

PREPEND – The contents of the active boot environment's
file are added to the beginning of the new boot environment's file. This addition
might lead to duplicate entries in the file. Directories can not be listed
as PREPEND. The new boot environment file has the same date, mode, and ownership
as the same file on the previous boot environment.

Forcing a Synchronization Between Boot
Environments

The first time you boot from a newly created boot environment, Solaris
Live Upgrade synchronizes the new boot environment with the boot environment
that was last active. After this initial boot and synchronization, Solaris
Live Upgrade does not perform a synchronization unless requested. To force
a synchronization, you use the luactivate command with
the -s option.

You might want to force a synchronization if you are maintaining multiple
versions of the Solaris OS. You might want changes in files such as email or passwd/group to be in the boot environment
you are activating to. If you force a synchronization, Solaris Live Upgrade
checks for conflicts between files that are subject to synchronization. When
the new boot environment is booted and a conflict is detected, a warning is
issued and the files are not synchronized. Activation can be completed successfully,
despite such a conflict. A conflict can occur if you make changes to the same
file on both the new boot environment and the active boot environment. For
example, you make changes to the /etc/passwd file on
the original boot environment. Then you make other changes to /etc/passwd file on the new boot environment. The synchronization process
cannot choose which file to copy for the synchronization.

Caution –

Use this option with great care, because you might not be
aware of or in control of changes that might have occurred in the last-active
boot environment. For example, if you were running Solaris 10 8/07 software
on your current boot environment and booted back to a Solaris 9 release with
a forced synchronization, files could be changed on the Solaris 9 release.
Because files are dependent on the release of the OS, the boot to the Solaris
9 release could fail because the Solaris 10 8/07 files might not
be compatible with the Solaris 9 files.